A 27-year-old nonsmoking woman complained of cough and chest oppression for two years since an episode of pneumonia. Clinical tests showed decrease in FEV1.0 during attacks of coughing and evidence of bronchial hypersensitivity. While these events fitted the picture of bronchial asthma, the nonwheezing cough suggested cough variant asthma. Antinuclear antibody and anti-ds DNA antibody were increased and leukopenia was recognized, suggesting the diagnosis of systemic lupus erythematosus (SLE). Bronchoalveolar lavage showed lymphocytic alveolitis and decreased T4/T8. These results were suggestive of collagen lung induced by SLE. Inhalation challenge with capsaicin and rapid intravenous injection of lobelin and alinamin indicated that peripheral c-fiber receptors were involved in the induction of coughing. We conclude that the peripheral lesion of collagen lung stimulates the peripheral c-fiber receptors, leading to cough variant asthma.